The embodiments described herein relate generally to power equipment protection devices and, more particularly, to apparatus for use in channeling exhaust gases and pressure away from a location of arc generation.
Known electric power circuits and switchgear generally have conductors that are separated by insulation, such as air, or gas or solid dielectrics. However, if the conductors are positioned too closely together, or if a voltage between the conductors exceeds the insulative properties of the insulation between the conductors, an arc can occur. The insulation between the conductors can become ionized, which makes the insulation conductive and enables formation of an arc flash.
An arc flash includes a rapid release of energy due to a fault between two phase conductors, between a phase conductor and a neutral conductor, or between a phase conductor and a ground point. Arc flash temperatures can reach or exceed 20,000° C., which can vaporize the conductors and adjacent equipment. Moreover, an arc flash can release significant energy in the form of heat, intense light, pressure waves, and/or sound waves, sufficient to damage the conductors and adjacent equipment. However, the current level of a fault that generates an arc flash is generally less than the current level of a short circuit, such that a circuit breaker may not trip or exhibits a delayed trip unless the circuit breaker is specifically designed to handle an arc fault condition.
Standard circuit protection devices, such as fuses and circuit breakers, generally do not react quickly enough to mitigate an arc flash. One known circuit protection device that exhibits a sufficiently rapid response is an electrical “crowbar,” which utilizes a mechanical and/or electro-mechanical process by intentionally creating an electrical “short circuit” to divert the electrical energy away from the arc flash point. Such an intentional short circuit fault is then cleared by tripping a fuse or a circuit breaker. However, the intentional short circuit fault created using a crowbar may allow significant levels of current to flow through adjacent electrical equipment, thereby still enabling damage to the equipment.
Another known circuit protection device that exhibits a sufficiently rapid response is an arc containment device, which creates a contained arc to divert the electrical energy away from the arc flash point. For example, some known devices generate an arc, such as a secondary arc flash, for use in dissipating energy associated with a primary arc flash detected on a circuit. At least some known arc containment devices include exhaust port that are positioned along a side surface to shorten an exhaust path away from the location where the contained arc is created and into the ambient. However, such venting schemes release hot gases at high pressure into an equipment enclosure, which can cause additional damage to other electronics modules within the same enclosure.
For at least the reasons stated above, a need exists for an arc containment device having an improved exhaust duct apparatus that directs exhaust gasses from an exhaust port on the arc containment device towards an optimized direction into an equipment enclosure.
Additionally, for at least the reasons stated above, a need exists for an arc containment device having an exhaust duct apparatus that is simple, robust, inexpensive, and without moving parts.